Hello My fellow Malters, I just got off the phone with Andre Fire Equipment in Sheboygan and they refill CO2 tanks. The cost for a 5lb tank is $9 per fill. You do have to call ahead of time because they have a limited staff, so they suggest you call ahead to make sure they are not out servicing customers. The office hours are 7am-3:30pm Mon-Fri. Here is the phone number. (920)452-6058. I know some guys just exchange their tanks at Airgas, but for those who purchased a nice new tank and don’t want to exchange it for an old one, this is a great cheap source of CO2.